Dual Effect of Structure and Hydration on Magnesium-Ion Insertion into Electrodeposited V 2 O 5 Thin Films
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Electrochemistry↗
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Systematic Study of the Cathode Compositional Dependency of Cross-Talk Behavior in Li-Ion Battery
While LiNi x Mn y Co 1-x-y O 2 (NMC) is one of the most widely used cathode materials for lithium-ion batteries (LIBs), the composition of NMC is evolving to Ni-rich NMC to achieve higher lithium capacity that fulfills the constant demand for LIBs with ever-higher energy densities. The change in the composition of NMC affects electrochemical features and electrode cross-talk, which explains the performance change during cycling. Here in this study, we introduce various NMC materials (LiNi 0.5 Mn 0.3 Co 0.2 O 2 , LiNi 0.6 Mn 0.2 Co 0.2 O 2 and LiNi 0.8 Mn 0.1 Co 0.1 O 2 ) to reveal how the NMC composition affects electrode cross-talk. The study reveals that NMC composition strongly affects transition metal dissolution; dissolution of manganese linearly decreases as its stoichiometric ratio in NMC decreases, while dissolution of nickel is only prominent in LiNi 0.8 Mn 0.1 Co 0.1 O 2 . Aged electrolyte samples are characterized with high-performance liquid chromatography, and two electrolyte decomposition species, C 8 H 16 O 5 and C 9 H 18 O 5 , are identified across all samples.
25 ENERGY STORAGE↗
Operando Synchrotron Studies of Inhomogeneity during Anode-Free Plating of Li Metal in Pouch Cell Batteries
Operando synchrotron X-ray diffraction (XRD) studies have not previously been used to directly characterize Li metal in standard batteries due to the extremely weak scattering from Li atoms. In this work, it is demonstrated the stripping and plating of Li metal can be effectively quantified during battery cycling in appropriately designed synchrotron XRD experiments that utilize an anode-free battery configuration in which a Li-containing cathode material of LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622) is paired with a bare anode current collector consisting of either Cu metal (Cu/NMC) or Mo metal (Mo/NMC). In this configuration, it is possible to probe local variations in the deposition and stripping of Li metal with sufficient spatial sensitivity to map the inhomogeneity in pouch cells and to follow these processes with sufficient time resolution to track state-of-charge-dependent variations in the rate of Li usage at a single point. For the Cu/NMC and Mo/NMC batteries, it was observed that the initial plating of Li occurred in a very homogeneous manner but that severe macroscopic inhomogeneity arose on a mm-scale during the subsequent stripping of Li, contrasting with the conventional wisdom that the greatest challenges in Li metal batteries are associated with Li deposition.
25 ENERGY STORAGE↗
All Solid-State Li/LLZO/LCO Battery Enabled by Alumina Interfacial Coating
Li 7 La 3 Zr 2 O 12 (LLZO) garnet-type lithium-ion conductors are being investigated as a promising solid electrolyte for solid-state lithium batteries. To enable a functional all-solid-state configuration intensive investigations are needed to reduce the cathode/electrolyte interfacial resistance which contributes the most to cell performance loss. Among the commercial cathode materials investigated so far, LiCoO 2 (LCO) is one of the most stable with garnet electrolytes as only a superficial reaction has been detected between the two materials. However, even this minor reaction would block the Li-ion transport through the interface, resulting in deteriorated cell performance. In this work, we demonstrate that a thin aluminum oxide layer (5 nm) can be an effective interlayer to impede the formation of a harmful interphase and enable facile Li-ion transfer between LCO and the LLZO garnet. Room-temperature-sputtered LCO thin films were employed to form an interface with the garnet electrolyte and annealed at 800 °C to reveal the effect of the interfacial reaction on the Li-ion transfer across the interface. An aluminum oxide layer was then introduced between LCO and the garnet electrolyte by sputtering a metallic aluminum layer which is then annealed together with the upper LCO layer in oxygen, or by direct atomic layer deposition of the oxide. Compared to the LCO/LLZO/Li cells without an aluminum oxide interlayer, those with the interlayer exhibited improved performance, i.e., a stable discharge capacity of up to 90 mAh/(g LCO) at a C/10 rate, a rate capability up to 1.68C and a stable galvanostatic cycling at 0.1C for over 100 cycles with a discharge capacity fade rate of 0.15% per cycle. It was determined that aluminum diffused into the LCO layer after preventing the initial detrimental reaction between LCO and the LLZO garnet from happening during high temperature annealing, suggesting that the coating does not have to remain a physically blocking layer during cycling to function.
Electrochemistry↗
Vibrational Entropy Contribution to Mixing Free Energy of Ni-Rich LiNi 1- y Co y O 2
First principles density-functional-theory calculations are performed of the mixing free energy of the layered oxide LiNi 1-y Co y O 2 , a model Li-ion-battery cathode material, at 1000 K. Analysis of internal energy, LN exchange, configurational entropy and vibrational entropy are combined to obtain the net mixing free energy. The vibrational entropy requires a more indirect treatment than the other terms; analysis based on heat capacity is presented here, to show that the vibrational entropy is of comparable magnitude to the configurational entropy, and it tends to promote solid-solution behavior in LiNi 1-y Co y O 2 .
25 ENERGY STORAGE↗
Revealing the Mechanism Behind Sudden Capacity Loss in Lithium Metal Batteries
Rechargeable Li-metal batteries (LMBs) are attractive energy storage candidates for electric vehicles (EVs) because they offer higher energy density than batteries built with intercalation electrodes. However, one of the main barriers to the commercial deployment of LMBs has been their relatively short cycle life. Re-designing the electrolyte system shows promise in achieving acceptable cycle life, but even so, the resulting cells display a challenging end-of-life (EOL) behavior: a sudden capacity loss. Herein, we report a new method for analyzing voltage profiles during cycling to distinguish between the capacity loss originating from the loss of cathode capacity vs growth in cell resistance. Further, this analysis reveals that sudden capacity loss was preceded by acceleration in the rate of growth of cell resistance, and cycling of multiple cells showed that this phenomenon is sensitive to the initial quantity of electrolyte in the cells. In contrast, the cathode capacity degraded at a constant rate independent of the electrolyte quantity. Combining this evidence with post-analysis of harvested electrolyte and electrodes, we conclude that neither the loss of active lithium nor the loss of active cathode material was the primary source of sudden capacity loss; instead, consumption and decomposition of electrolyte causes the drastic capacity loss at EOL.
25 ENERGY STORAGE↗
The Sensitivity of Nickel Substitution in the Structural Design of Manganese-Based Layered and Lithiated Spinel Electrodes for Li-Ion Batteries
A concerted effort is being made at Argonne National Laboratory to explore and develop high-performance lithium-manganese-nickel-oxide cathode materials for the lithium battery industry. They are both energy- and cost-competitive relative to cobalt- and nickel-rich systems, such as LiCoO 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , and LiNi 0.8 Mn 0.1 Co 0.1 O 2 . The recent discovery of the structural versatility of LiNi 0.5 Mn 0.5 O 2 , has revealed that it can exist in three configurations: lithiated spinel, partially disordered layered, and completely disordered rock salt within a common cubic-close-packed oxygen array. This versatility opens up the possibility of designing structurally integrated electrode components with interlinking 2-D (layered) and 3-D (spinel) channels for Li-ion transport. This paper highlights the sensitivity of Ni substitution and synthesis temperature on the structural and electrochemical properties of LiNi 0.50 Mn 0.50 O 2 , LiNi 0.53 Mn 0.47 O 2 , LiNi 0.47 Mn 0.53 O 2 , and LiNi 0.25 Mn 0.75 O 2 electrodes, as well as a cobalt-containing composition, LiNi 0.333 Mn 0.333 Co 0.333 O 2 , when synthesized at a relatively low temperature of 400 °C.
25 ENERGY STORAGE↗
Intermetallic PtCo Catalysts with Enhanced Performance and Stability [Slides]
Pt-based catalysts need systematic modifications to be adapted to different applications (LDV or HDV). L1 0 -CoPt particles have been demonstrated as highly active and durable cathode materials for fuel cells. Colloidal synthesis can generate catalysts with highly uniform particles size but the removal of surfactants is challenging. Acid leaching warrants a Pt shell with certain thickness, which mitigates the Co leaching. Controlling the size of L1 0 -CoPt particles is a robust method to alter their catalytic behaviours and tailor the function of catalysts. Modifying the carbon features (e.g. porosity and graphitization) is an effective method to regulate the performance and stability of catalysts to adapt the catalysts to different applications.
30 DIRECT ENERGY CONVERSION↗
Cobalt-Free Cathodes for Next Generation Li-Ion Batteries
In this U.S. Department of Energy sponsored project Nexceris, in collaboration with project partners; The Ohio State University and Navitas Advanced Systems have advanced the technical maturity of a non-cobalt containing cathode for next-generation Li-ion batteries. The cathode is based on the lithium manganese nickel-titanium oxide, LiNi 0.5 Mn 1.5 TiO 4 (LNMTO) high voltage spinel. To address limitations with poor cycle and calendar life an microstucturally hierarchical LNMO/LNMTO core-shell cathode powder has been developed that enables the formation of a solid-electrolyte interface that effectively passivates the cathode surface. The microstructural enhancements of the cathode material focus on preferentially enriching the surface with titanium. In parallel, new, optimized binder and electrolyte chemistries have been incorporated to address degradation mechanisms associated with high-voltage systems. Single-layer pouch cell and large-format 2-Ah cell testing have shown that an optimized LNMO/LNMTO core-shell powder significantly improves initial cell capacity and cycle life compared to homogeneous LNMO powder. To support development and the fabrication of 2-Ah cells a novel Hybrid Alternative Wet-Chemical Synthesis (HAWCS) process have been developed. This low-cost, synthesis approach enables the excellent compositional and particle morphology control achieved with co-precipitation without the strict process controls and associated expensive process equipment.
25 ENERGY STORAGE↗
An AFM study of Zn/MnO 2 Co-deposition (ORISE Internship Report)
With the growing demand for rechargeable batteries, the aqueous Zn-ion battery has shown promise as a cheaper and safer alternative to modern Li-ion batteries. Meanwhile, for developing batteries with optimal charge transfer, electrodes with interpenetrating geometries have been explored to minimize the distance traveled by ions in the electrolyte. Creating a Zn-ion battery with interpenetrating electrodes may allow for more efficient cycling, but requires the co-deposition of anode and cathode materials. Because of the highly sensitive nature of electrodeposition, the presence of additional ions may have an impact on the success and homogeneity of cathode/anode deposition, possibly preventing the proper function of an interpenetrating Zn battery. This study examined the effects of added ions on Zn deposition through in situ Atomic Force Microscopy with the goal of determining whether the co-deposition of Zn and MnO 2 is a viable option for electrodes with interpenetrating geometries. Solutions of 1M ZnSO 4 and 1M ZnSO 4 + 0.1M C 4 H 6 MnO 4 were made to simulate normal and co-deposition conditions. Layers of Zn were electrodeposited onto a Cu microelectrode at a current density of 10mA cm -2 with intermittent AFM imaging after 50 deposited monolayers. The presence of manganese acetate (C 4 H 6 MnO 4 ) was found to decrease Zn nucleation size on the Cu UME, suggesting the presence of C 4 H 6 MnO 4 would not negatively impact the co-deposition of Zn and MnO 2 .
25 ENERGY STORAGE↗
On the Life Expectancy of High-Power CW magnetrons for Superconducting Accelerators*
Utilization of the high-power CW magnetrons as RF sources in SRF accelerators was proposed in a number of works, e.g., [1, 2]. But typically, the CW high-power magnetrons are designed as RF sources for industrial heating, and the lifetime of the tubes is not the first priority as it is required for high-energy accelerators. The high-power CW magnetrons use cathodes made of pure tungsten. The emission properties of the tungsten cathodes are not deteriorated much by electron and ion bombardment, but the latter causes sputtering of the cathode in the magnetron crossed fields. The sputtered cathode material covers the magnetron interior. That leads to sparks and discharges in a magnetron limiting its lifetime. Thus, the life expectancy estimates are highly important for application of CW magnetrons in SRF accelerator projects.
43 PARTICLE ACCELERATORS↗
High-Energy and High-Power NMP-Free, Designer NMC 811 Cathodes with Ultra-Thick Architectures Processed by Electrophoretic Deposition
This project focused on electrode engineering and reducing the weight of inactive components in the battery cells. Additionally, the project focused on optimizing the ‘electrophoretic deposition’ technique developed by PPG industries for aqueous processing of electrodes. During this project team has screened several binders suitable for electrophoretic deposition of electrodes. Additionally, we developed a nice strategy to deposit a low cost and scalable oxide coating on the surface of cathode materials. ORNL team performed the research under this CRADA at DOE’s Battery Manufacturing Facility (BMF) at ORNL.
99 GENERAL AND MISCELLANEOUS↗
High-Energy and High-Power NMP-Free, Designer NMC 811 Cathodes with Ultra-Thick Architectures Processed by Electrophoretic Deposition
This project focused on electrode engineering and reducing the weight of inactive components in the battery cells. Additionally, the project focused on optimizing the ‘electrophoretic deposition’ technique developed by PPG industries for aqueous processing of electrodes. During this project team has screened several binders suitable for electrophoretic deposition of electrodes. Additionally, we developed a nice strategy to deposit a low cost and scalable oxide coating on the surface of cathode materials. ORNL team performed the research under this CRADA at DOE’s Battery Manufacturing Facility (BMF) at ORNL.
25 ENERGY STORAGE↗
Aspects of Spodumene Lithium Extraction Techniques
Lithium (Li), a leading cathode material in rechargeable Li-ion batteries, is vital to modern energy storage technology, establishing it as one of the most impactful and strategical elements. Given the surge in the electric car market, it is crucial to improve lithium recovery from its rich mineral deposits using the most effective extraction technique. In recent years, both industry and academia have shown significant interest in Li recovery from various Li-bearing minerals. Of these, only extraction from spodumene has established a reliable industrial production of Li salts. The current approaches for cracking of the naturally occurring, stable α-spodumene structure into a more open structure—β-spodumene—involve the so-called decrepitation process that takes place at extreme temperatures of ~1100 °C. This conversion is necessary, as β-spodumene is more susceptible to chemical attacks facilitating Li extraction. In the last several decades, many techniques have been demonstrated and patented to process hard-rock mineral spodumene. The objective of this review is to present a thorough analysis of significant findings and the enhancement of process flowsheets over time that can be useful for both research endeavors and industrial process improvements. The review focuses on the following techniques: acid methods, alkali methods, carbonate roasting/autoclaving methods, sulfuric acid roasting/autoclaving methods, chlorinating methods, and mechanochemical activation. Recently, microwaves (MWs), as an energy source, have been employed to transform α-spodumene into β-spodumene. Considering its energy-efficient and short-duration aspects, the review discusses the interaction mechanism of MWs with solids, MW-assisted decrepitation, and Li extraction efficiencies. Finally, the merits and/or disadvantages, challenges, and prospects of the processes are summarized.
25 ENERGY STORAGE↗
Encapsulated sulfur cathodes for rechargeable lithium batteries
A method of forming a sulfur-based cathode material includes: 1) providing a sulfur-based nanostructure; 2) coating the nanostructure with an encapsulating material to form a shell surrounding the nanostructure; and 3) removing a portion of the nanostructure through the shell to form a void within the shell, with a remaining portion of the nanostructure disposed within the shell.
25 ENERGY STORAGE↗
Encapsulated sulfur cathodes for rechargeable lithium batteries
A method of forming a sulfur-based cathode material includes: 1) providing a sulfur-based nanostructure; 2) coating the nanostructure with an encapsulating material to form a shell surrounding the nanostructure; and 3) removing a portion of the nanostructure through the shell to form a void within the shell, with a remaining portion of the nanostructure disposed within the shell.
Li, Weiyang↗
ϵ-VOPO 4 cathode for lithium ion batteries
The epsilon polymorph of vanadyl phosphate, ε-VOPO 4 , made from the solvothermally synthesized H 2 VOPO 4 , is a high density cathode material for lithium-ion batteries optimized to reversibly intercalate two Li-ions to reach the full theoretical capacity at least 50 cycles with a coulombic efficiency of 98%. This material adopts a stable 3D tunnel structure and can extract two Li-ions per vanadium ion, giving a theoretical capacity of 305 mAh/g, with an upper charge/discharge plateau at around 4.0 V, and one lower at around 2.5 V.
25 ENERGY STORAGE↗
Process for making manganese dioxide and its polymorphs reversible
A method of forming a layered manganese dioxide for use in a cathode of a battery comprises disposing a cathode into a housing of an electrochemical cell, disposing an anode into the housing, disposing a polymeric separator between the anode and the cathode such that the anode and the cathode are electrically separated, adding an alkaline electrolyte to the housing, cycling the electrochemical cell into the 2nd electron capacity of the manganese dioxide, and forming a layered manganese dioxide having a layered manganese dioxide structure with the one or more additives incorporated into the layered manganese dioxide structure. The cathode comprising a cathode material comprising: a manganese dioxide compound, one or more additives selected from the group consisting of bismuth, copper, tin, lead, silver, cobalt, nickel, magnesium, aluminum, potassium, lithium, calcium, gold, antimony, iron, zinc, and combinations thereof, and a conductive carbon.
Yadav, Gautam G.↗